The present invention relates generally to methods and apparatus for interactively displaying book-like documents on pointer-based computer systems such as pen-based computers. The book-like documents may have one or more tools for navigating through their contents quickly. The contents of such documents may include text, graphics, "live" action templates, etc.
A pen-based computer is a small, often hand-held, computer system where the primary method for inputting data includes a "pen" or stylus. A typical pen-based computer system is housed in a generally rectangular enclosure, and has a dual-function display assembly providing a viewing screen along one of the planar sides of the enclosure. The dual-function display assembly serves as both an input device and an output device. When operating as an input device, the display assembly senses the position of the tip of the stylus on the viewing screen and provides this positional information to the computer's central processing unit (CPU). Some display assemblies can also sense the pressure of the stylus on the screen to provide further information to the CPU. When operating as an output device, the display assembly presents computer-generated images on the screen.
The dual-function display assemblies of pen-based computer systems permit users to operate the computers as a computerized notepads. For example, graphical images can be input into the pen-based computer by merely moving the stylus on the surface of the screen. As the CPU senses the position and movement of the stylus, it generates a corresponding image on the screen to create the illusion that the stylus is drawing the image directly upon the screen, i.e. that the stylus is "inking" an image on the screen. With suitable recognition software, text and numeric information can also be entered into the pen-based computer system in a similar fashion.
Such computer systems have many uses: they can be used to jot down notes at meetings, organize to-do lists, send and receive information by faxing, electronic mail, etc. Because computer systems such as these are an integral part of many user's lives, it would also be desirable if they could be used to store and display book-like information such as novels and reference materials (i.e., electronic books). This would be especially desirable in pen-based computer systems which recognize handwritten instructions and allow the user to scribble handwritten notes and interact with "live" screens which might be incorporated into the books.
Suitable materials for use as "electronic books" might include interactive almanacs, encyclopedias, and other reference materials such as lists of phone numbers for various consumer services or government agencies. Unfortunately, books and reference materials such as these can become large and unwieldy, especially without careful organization. Thus, it would be useful to have specialized tools for navigating throughout the content of an electronic book. "Find" methods are now available for searching all text content within a document to locate specific character strings, but these methods are often too slow or unfocused to quickly take the user to a desired location. It would therefore be desirable to include in electronic books one or more high-level navigation systems that quickly show the user where he or she is located within the book, what other material is available in the book, and how to get to other locations in the book.